Rod-supporting chair for continuously reinforced concrete paving



Dec. 17, 1963 REINFORCED CONCRETE PAVING Filed May 29, 1961 INVENTOR:EORGE J. ERIKSSON G BY United States Patent 3,114,221 ROD-SUPPGRTENG(SHARK FUR QGNTENUGUSLY REINFORCED CGNCRETE PAVEJG George .F. Erilrasen,Morton Grove, Eli, assignor to Superior Concrete Accessories, Zine,Franklin Paris, EL,

a corporation of Delaware Filed May 29, 196.1, Ser. No. 113,491 1 Claim.(Cl. 50-514) The present invention relates to concrete reinforcing meansand more particularly to a rod-supporting chair which is adapted to bepositioned on a subgrade and, in combination with like chairs, serves tosupport at a predetermined level above the subgrade a series ofreinforcing rods in connection with a concrete paving installation.

It is among the general objects of the present invention to provide animproved reinforcing rod-supporting chair which, due to the novel designand construction thereof, will more accurately support a reinforcing rodat a predetermined height above the subgrade, height being a criticalfactor in many installations. A similar and related object of theinvention is to provide such a rodsupporting chair which is stronger andmore rigid than present-day chairs for the same purpose.

One or" the principal and specific objects of the invention is toprovide a rod-supporting chair having associated therewith novel lockingmeans for retaining a reinforcing rod in position on the chair in theupper region thereof, such locking means being automatically effectiveupon downward pushing of the rod into the rod-receiving cradle which isprovided for it at the upper end of the chair legs.

Another and important object of the invention is to provide in a chairof this character a novel sand plate which forms a base support for thechair legs and by means of which a more effective welded connectionbetween the legs and the sand plate may be attained than has heretoforebeen possible.

Yet another object of the invention is to provide in a chair of the typeunder consideration a novel rod-receiving cradle which is of one piececonstruction and is in the form of a sheet metal stamping, and whereinthe previously-referred to locking means for the rod which is associatedtherewith is inherent in the stamping itself and is created at the timethe stamping operation is performed.

A still further object is to provide such a rod-supporting chair havingassociated therewith a rod-receiving cradle which is of the snap-in typeand embodies a bendable wraparound tab on one of the cradle arms or sideportions, the tab being conveniently accessible to the foot of theoperator for bending purposes.

The provision of a reinforcing rod-supporting chair which is extremelysimple in its construction and is compriscd of but three parts,available from commercial flat sheet stock and round rod stock, thuscontributing toward economy of manufacture; one which is rugged anddurable and, therefore, will withstand rough usage; one which requiresno machining in its manufacture; and one which is well-adatped toperform the services required of it, are further desiderata which havebeen borne in mind in the production and development of therod-supporting chair constituting the present invention.

Other objects of the invention and the various advantages andcharacteristics thereof will be apparent from a consideration of thefollowing description.

In the accompanying single sheet of drawing forming a part of thisspecification, one embodiment of the invention has been shown. a

In this drawing:

FIG. 1 is a sectional view taken vertically and longitudinally through aconcrete paving installation and show 3,114,22l Patented Dec. 17, 1963ing one of the improved rod-suporting chairs of the present inventionoperatively associated therewith, the chair being shown in sideelevation;

H6. 2 is a vertical section taken on the line 22 of PEG. 1, the rodbeing shown in dotted lines or phantom and the concrete removed in theinterests of clarity;

PEG. 3 is a top plan view of the chair, the rod being shown in phantom;

FIG. 4 is a sectional view taken on the line 4-4 of FIG. 1, the rodbeing shown in phantom and the concrete removed;

FIG. 5 is an enlarged sectional View of the upper portion of the chairshown in FIG. 1; and

FIG. 6 is a sectional view similar to FIG. 5 but illustrating the mannerin which the wrap-around tab of the chair cradle is made eifective.

Referring now to the drawing in detail, and in particular to FIG. 1,wherein an exemplary form of reinforcing rod-supporting chairconstructed in accordance with the principles of the present inventionhas been shown as being operatively installed in a paving construction,the chair assembly has been designated in its entirety at it and isshown as being supported on a subgrade 12 and supporting a cylindrical,horizontal, transversely extending, reinforcing rod 14. The horizontal,transversely extending, reinforcing rod 14 serves to support thereon oneor more horizontal, longitudinally extending, reinforcing rods 16 in theusual manner of pavement reinforcement. The chair assembly if; and therods 14 and it? in associated relation therewith are shown as beingembedded in the concrete 18 of the paving installation on the subgrade12.

Referring now to the additional view of the drawing, the chair assemblyif) is comprised of but three parts, namely, a lower sand plate 2%,, anupper cradle 22, and an intermediate interconnecting leg support 24, thethree parts being welded together in a manner that will be describedpresently. The leg support and the sandplate constitute a lowersupporting base for the cradle.

Briefly, the cradle 22 is in the form of a sheet metal stamping which isgenerally U-shaped in transverse cross section as viewed in F568. 1 andS and is formed from a flat rectangular sheet of metal stock,preferably, spring steel. The upper end of the cradle is open and therod lid is adapted to be pushed downwards through the open end of thecradle and to seat within the bottom regions of the cradle. The legsupport 24 of the chair It) is formed from a length of cylindrical steelrod stock which is bent intermediate its ends to provide an invertedgenerally U-shaped structure having an upper bight or crest portion 26from which there extend downwardly and outwardly in diverging fashion apair of straight legs proper 23 having laterally turned foot portionsSil at their lower ends. The foot portions 3i) are welded as at 32 tothe sand plate 2%, while the crest portion at of the leg support 2-6 iswelded as at 34 to the lower regions of the cradle 22.

More specifically, the U-shaped cradle 22; is provided with a bightportion 36 which is of relatively small radius of curvature and fromwhich there extend upwardly two side portion 38 and 49, such sideportions being generally curved on a longer radius of curvature andapproximating that of the cylindrical, transversely extending,reinforcing rod 14 which is received within the cradle. The upper regionof the curved side portion 40 merges with an outwardly and upwardlyinclined, fiat, wrap-around terminal flap 42 (see PKG. 5), the functionof which will be made clear hereafter. The upper portion of the curvedside portion 38 of the cradle is turned outwardly and is designated bythe reference numeral 44. The over-all extent of the side portion 49 andthe wrap-around flap 42 is greater than the overall extent of the sideportion 38 and the outwardly turned portion 44 so that, in the freestate of the cradle 22, the upper edge of the flap 42 is higher than theupper edge of the outwardly turned portion 44.

As best seen in FEG. 5, the upper regions of the two curved sideportions 38 and are closer together than the diameter of thetransversely extending reinforcing rod 14, and as the result, a snap-ineffect is produced when the rod 14 is pressed downwards into theresilient cradle 22.

' This snap-in effect cannot, however, be relied upon to maintain therod seated within the cradle under actual installation conditions wherethere may be a tendency for the wet poured concrete to float the rod, orwhere tamping or vibrating mechanism is employed to settle the concrete.Therefore, according to the present invention, locking means is providedfor positively locking the transversely extending reinforcing rod 14within the confines of the cradle and this means becomes automaticallyeffective as soon as the reinforcing rod is pushed downwards into thecradle through the open upper end thereof. Accordingly, as best seen inFIGS. 3, .4 and 5, the opposite side edges of the cradle side portion4-0, which includes the wrap-around flap 42, is formed with relativelyshort, horizontally aligned, inwardly extending slits 5i) therein, andthe metal of the side portion 49 immediately above each slit is turnedinwardly to form an inturned portion 52. These inturned portions 52constitute detents or friction tabs which are designed frictionally toengage the cylindrical wall or" the reinforcing rod 14 and preventupward movement of the same within the cradle 22. During downwardinsertion of the rod 14 into the cradle 22, these friction tabs willyield or be displaced outwards under the spreading influence of the rodand, after the rod has been received within the cradle and bottomedtherein to the fullest extent of which it is capable, the friction tabs52 will snap inwards and engage in overlying relation respectiveportions of the rod and hold the rod securely in position within thecradle.

Still referring, for convenience of illustration, to FIG. 5, the bightportion 36 of small curvature is connected by the weld 34 to thecrestportion 26 of the leg support 24, the two curved meeting surfaces beingadmirably welladapted for resistance welding operations where thesharper of the curved portions of each of the two curved parts sinl s,so to speak, into the metal of the other part at a region where thecurvature is not so great. Thus, the sharply curved bight portion 36 hasa tendency to penetrate the metal of the leg support in the arcuatecrest portion 26 thereof, and the curved small diameter cylindricalsurface of the rod stock of the leg support tends to penetrate thelesser curved bight portion 36. By virtue of these phenomena, there is atendency for each part to flow into the other part during the effectingof the resistance weld.

Referring now to FIGS. 1, 3 and 4, the sand plate is in the form of asheet metal stamping (preferably steel) and is made from an elongatedrectangular strip of fiat sheet metal stock. At a distance spacedslightly inwardly from each longitudinal edge of the plate a raised rib663 is formed, the two ribs being coextensive with the longitudinalextent of the plate. Each end region of the plate is formed with aseries of transverse raised ribs 62. While five such ribs have beenillustrated herein at each end region of the plate, it will beunderstood that a greater or lesser number thereof may be employed ifdesired. The ribs 62 extend between the two ribs 65) and completelybridge the distance between these two last mentioned ribs. A hole 64-may be formed in the medial region of th plate to adapt the cha n forfastening by means of a nail or the like to certain types of subgradescapable of receiving a nail therein.

The laterally turned foot portions 353 of the leg support 24 overlie thetwo transversely ribbed portions of the sand plate and are welded byresistance welding to the ribs thereof. The foot portions 3d overlie andextend transversely of tl c ribs 62 and the relatively sharp curvatureof the transverse ribs afford the necessary sharp projections wh ch areessential to a strong and eificient resistance d weld. When welding heatand pressure are applied to the foot portions and to the transverselyribbed portions, the foot portions literally burn into the ribs andestablish an extremely effective weld which is coext nsive with the footportions.

Referring now to FIGS. 1, 5 and 6, in effecting any given paving orother installation, the requisite number of the chair assemblies 1% arepositioned upon the subgrade 12 and then fastened, if desired, in theirproper selected positions. Thereafter, the transversely extending rods34 may be placed across the cradles 22 of the trans versely alignedchair assemblies. Insofar as each chair assembly 1-) is concerned, therod lid may be pressed downwards into the open upper side of the cradle22 by the utilization of foot pressure, the rod being pressed downwardlyin the cradle until it snaps into position beneath the inwardly turned,tab-forming portions 52 (see FIG. 5). The concrete may then be poured.

in certain instances, especially where vibratory devices are employedfor concrete settling purposes, it may be found expedient to insureagainst dislodgment of the rod 14 from the cradles 22 under theinfluence of vibration or rod-fioating by bending the wrap-around flaps42 over the upper regions of the rod. This may be accomplishedexpeditiously by merely placing the foot against the upstandingwrap-around flap d2 of each chair assembly 19 as indicated at F in FiG.5 and, by the application of foot pressure to the flap pushing the samefrom the approximately tangential position which it normally assumeswith respect to the rod 14, to the position wherein it is shown in PEG.6. in such an instance, the inturned portions 52 will bite into themetal of the rod 14 and cause the rod to be held securely within thecradle.

It is to be noted at this pointthat in the manufacture of the sheetmetal cradle 22, the slitting thereof at 5:9 and the bending of theportions 52 out of the plane of the adjacent portion of the blank fromwhich the cradle is formed may be accomplished in one operation,utilizing a single pair of stamping and severing dies. No excess orwaste material is involved in the stamping operation. The sand platelikewise may be formed by a single stamping operation. Because of thesefacts and because the chair assembly 1:) is comprised of but the threeparts and assembled by efficient welding operations, the assembly is onewhich may be manufactured economically in quantity at a low cost.

The invention is not to be limited to the exact arrangement of partsshown in the accompanying drawing or described in this specification asvarious changes in the details of construction may be resorted towithout departing from the spirit or scope of the invention. Therefore,only insofar as the invention has particularly been pointed out in theaccompanying claim is the same to be limited.

Having thus described the invention what I claim as new and desire tosecure by Letters Patent is:

As a new article of manufacture, a three-part composite chair formaintaining a cylindrical, horizontally extending, reinforcing rod infixed position over a subgrade in connection with a paving installation,said chair comprising a lower sand plate adapted to be supported uponthe subgrade, an upper cradle, and an intermediate interconnecting legsupport, said sand plate being in the form of a generally rectangular,elongated, sheet metal stamping having a pal" of marginal upstruckreinforcing ribs along its side edges and, in addition, having a seriesof transversely extending upstruck ribs extending between said marginalribs at each of its end regions, said leg support comprising a length ofcylindrical steel rod stock bent to'inverted U-shaped configuration andincluding a pair of'downwardly and outwardly diverging legs and aninterconnecting bight portion at the upper ends of the legs, the extremelower ends of said legs being turned outwardly away from each other andproviding a pair of horizontally extending foot portions, said footportions being seated upon the respective series of transverselyextending ribs at the end regions of the sand plate respectively andbeing resistance-welded thereto, said upper cradle being in the form ofa sheet metal stamping capable of deformation but possessing anappreciable degree of resilience, said latter stamping being bentmedially of its ends to provide a U-shaped trough-like member havingupwardly extending, spaced apart side portions and an interconnectingbight portion, the marginal side edges of one of said side portionsbeing formed with a pair of horizontally aligned slits therein whichextend inwardly from said side edges a slight distance, the metal of thelastmentioned stamping immediately above the slits being turned inwardlyof the cradle confines to provide a pair of rod-engaging friction tabs,said side portions being adapted to yield laterally under the influenceof the spreading action of the reinforcing rod as the latter is presseddownwards into the cradle to allow said friction tabs to move tooverlying positions above the rod and into firm frictional contacttherewith when the rod is in fully seated relation within the cradle,said bight portion of the cradle being seated upon the bight portion ofthe leg support with the axes of the two bight portions extending inparallelism, said two bight portions being resistance-welded together.

References Cited in the file of this patent UNITED STATES PATENTS

